Selective area epitaxy (SAE) has been used in the fabrication of advanced devices and circuits including, for example, edge emitting lasers, buried heterostructure lasers, patterned nanostructures, and integrated optoelectronic devices. In an SAE process, a dielectric mask defines window areas on a substrate. Using chemical beam epitaxy (CBE) or metalorganic chemical vapor deposition (MOCVD), eptaxial growth is then confined to those window areas.
Problems arise, however, because common dielectric mask materials such as SiO2 or SiNx require an ex-situ hydrofluoric acid etch for removal. Moreover, processing schemes typically involve several sample transfer steps to accommodate oxide layer deposition and patterning outside of the growth chamber, a SAE in the growth chamber, followed by mask removal outside of the growth chamber and finally, an overgrowth process. Each exposure of the growth surface to atmosphere can result in contamination that leads to surface degradation, traps, and nonradiative recombination centers.
Thus, there is a need to overcome these and other problems of the prior art to provide a method to remove a mask material using an in-situ etch step that minimizes both the atmospheric exposure of a growth surface and the number of sample transfers.